Flexible thermoelectric materials and devices hold enormous potential for wearable electronics but are hindered by inadequate material properties and inefficient assembly techniques, leading to suboptimal performance. Herein, we developed a flexible thermoelectric film, comprising AgSe nanowires as the primary material, a nylon membrane as a flexible scaffold, and reduced graphene oxide as a conductive network, achieving a record-high room-temperature ZT of 1.28. Hot-pressed AgSe nanowires exhibited strong (013) orientation, enhancing carrier mobility and electrical conductivity. Dispersed reduced graphene oxide further boosts electrical conductivity and induces an energy-filtering effect, decoupling electrical conductivity and the Seebeck coefficient to achieve an impressive power factor of 37 μW cm K at 300 K. The high-intensity between AgSe and reduced graphene oxide interfaces enhance phonon scattering, effectively reducing thermal conductivity to below 0.9 W m K and enabling the high ZT value. The nylon membrane endowed the film with exceptional flexibility. A large-scale out-of-plane device with 100 pairs of thermoelectric legs, assembled from these films, delivers an ultrahigh normalized power density of >9.8 μW cm K, outperforming all reported AgSe-based flexible devices. When applied to the human body, the device generated sufficient power to operate a thermo-hygrometer and a wristwatch, demonstrating its practical potential for wearable electronics.